hy do anyone know a I don't know the gener but its straight love story about a boy and a g...

hy do anyone know a I don't know the gener but its straight love story about a boy and a girl both are like serious type and I only remember the end I read so in the end they were playing a game like pubg with school in real life the boy got injured so girl go out to defeat the enemy students and she do a hit kill (duplicate gun with colors) so at the end she got shoot I only remember this much and

the character are boy is blonde and girl is black hair please help